Flocculating properties

Immiscible wetting in mixers Sol-gel processes Pellet flocculation <0.3 Low Up to 10 ton/hr Wet processing based on flocculation properties of particulate feed Coal fines, soot and oil removal from water Metal dicarhide, silica hydrogels Waste sludges and slurries... 

Flocculation Where dispersants are present at too high an active level in a boiler (say, when the actives exceed 80-100 ppm or possibly up to 120 ppm), the dispersant may exhibit flocculating properties normally dispersed sludges then settle out on boiler surfaces. 

In terms of measuring emulsion microstructure, ultrasonics is complementary to NMRI in that it is sensitive to droplet flocculation [54], which is the aggregation of droplets into clusters, or floes, without the occurrence of droplet fusion, or coalescence, as described earlier. Flocculation is an emulsion destabilization mechanism because it disrupts the uniform dispersion of discrete droplets. Furthermore, flocculation promotes creaming in the emulsion, as large clusters of droplets separate rapidly from the continuous phase, and also promotes coalescence, because droplets inside the clusters are in close contact for long periods of time. Ideally, a full characterization of an emulsion would include NMRI measurements of droplet size distributions, which only depend on the interior dimensions of the droplets and therefore are independent of flocculation, and also ultrasonic spectroscopy, which can characterize flocculation properties. 

Adsorption of nonionic and anionic polyacrylamides on kaolinite clay is studied together with various flocculation properties (settling rate, sediment volume, supernatant clarity and suspension viscosity) under controlled conditions of pH, ionic strength and agitation. Adsorption and flocculation data obtained simultaneously for selected systems were correlated to obtain information on the dependence of flocculation on the surface coverage. Interestingly, optimum polymer concentration and type vary depending upon the flocculation response that is monitored. This is discussed in terms of the different properties of the floes and the floe network that control different flocculation responses. Flocculation itself is examined as the cumulative result of many subprocesses that can depend differently on system properties. 

Photochromic sulfones 67 (R = CH3, C3H7) can be encapsulated into iron oxide particles to form unique multifunctional nanosystems having, for example, fluorescence, magnetic, and flocculation properties (08CC4622). 

When mixed-phase rutile pigments are used in special paint systems, (e.g., stoving or acid-catalyzed lacquers), inorganic surface treatment in an aqueous medium can improve the gloss and flocculation properties. For example, an aqueous pigment suspension is first treated with a surfactant, and then coated with metal hydroxides or oxide hydrates [3.93],... 

Chitosan possesses flocculating properties, which are used in water processing engineering as a part of the filtration process. It may remove phosphorus, heavy minerals and oils from the water. In the same manner, it is used to clarify wine (as a substitute for egg albumin) and beer. 

The flocculating properties of resins from barium ferrite and y-iron oxide are similar. Even diough the magnetized resin is flocculated, the floes break up readily when stirred so that the particles react more rapidly than standard-sized resin beads which are 300-1200 pm in diameter (Fig. 2). The shell configuration of whisker-type resins also enhances reaction r tes. Because of the magnetic flocculation phenomenon the magnetized beads separate out much more rapidly than the unmagnetized ones (Fig. 3). 

Popov. K.. Production of new polymer products with flocculating properties by the Mannich amino methylation of prehydiolized ternary acrylonitrile-methyl methacrylate-sodium vinylsulfonate copolymers. Tr. Vo-dosnahdyavane, Kamliz. Sanil. Tekh., 12, 119, 1977 Chem. Absir., 87, 18.5004, 1977. 

Among N-Mannich bases, derivatives of polyacrylamide (517) are investigated particularly for their flocculant properties in water treatment. The corresponding quaternary ammonium salts are also used. Benzimidazolic and bcnzotriazolic Mannich bases 518, usually with the bulky alkyl group linked to the amine moiety, are used effectively against corrosion in a manner similar to alkylphenols 513, which have the apolar group linked to the substrate moiety. 

This calculated efficiency factor provides only a relative measure of the properties of the floes formed. It was used tentatively to quantify the i/-axis of the schematic in Figure 1. Other methods of describing floe properties by one parameter, such as floe strength, would be similarly limited in furnishing insight into the coagulating and flocculating properties of the suspensions. 

Meanwhile, polymer molecular mass (M) decreases and duration of the process (t) as well (Figure 1). We continued flocculant synthesis until the volume of reaction solution stopped decreasing. The further prolongation of synthesis results in gradual increase of that volume due to hydrolysis of amide groups and formation of acrylic acid elements in the polymer. Sulphuric acid concentration also affects solubility and flocculating properties of the product. 

It should be noted that if the flocculant is water soluble then diapason of acid content is rather narrow. The width of this diapason depends of initial concentration of AN and the higher concentration is the narrower is diapason. It makes synthesis of water soluble flocculant with high polymer content more difficult. As the acid concentration increased flocculating properties of product kept increasing at first (due to increase in velocity of precipitation of suspended particles of black copper oxide and decrease of residual suspended materials concentration), but then started to decrease. Both characteristics of flocculating activity reached their extreme value during the same acid concentration which did not depend on initial AN content. 

The flocculant that is obtained as a product of aforementioned process contained a small amount of polymer that plays an integral role in the process of suspended particles precipitation. To find out if we can increase its content in the product we investigated how initial concentration of AN affects synthesis kinetics and flocculant s properties. We found out that increase of concentration of initial monomer results in increase of reaction s rate, polymer s content (P) and its molecular mass and in decrease of duration of process and improvement of flocculating properties (Figure 3). 

Increase in temperature results in increase of reaction s rate (active activation energy 83 kj per mole), decrease of its duration and of polymer s molecular mass as well as flocculating properties both velocity of precipitation of suspended particles and purification rate decreased (residual suspended materials concentration increased) (Figure 4). 

The effect of different flocculants particle size on flocculation properties... 

Trimethylchitosan ammonium Quaternisation of CS with methyl iodide in sodium hydroxide under controlled conditions Water-soluble over all the practical pH range Used in the paper industry due to good flocculating properties... 

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